Well drilling bit



United States Patent llei'erences Cited UNITED STATES PATENTS 2,657,016 10/1953 Grable.....

Charles T. White Qunnah,Texas [211 App]. No. 724,742 [22] Filed [72] Inventor April 29, 1968 [45] Patented Nov. 24, 1970 [73] Assignee WaIker-Neer Manufacturing (30., Inc.,

Wichita Falls, Texas a corporation of Texas [54 WELL DRILLING BIT 4 claimsfl Drawing 88. I ABSTRACT: Combination of a bit having cone shaped cut- [52] ,U.S.

ters, and a special sub forming an adapter whereby the bit is connected to the lower end of a string of drill pipe. The bit and the sub therefore are intended for use in an arrangement in which a string of tubing is arranged within the drill pipe and drilling fluid is circulated downw ardly through the annulus [50] Field between the drill pipe and the tubing, out through the bit, and

- up through the tubing.

1 ill iliiillilillui ltltlkll ii Patnt'ed Nov. 24, 1-970 CHARLES T WHITE INVENTOR.

ATTORNEY WELL DRILLING BIT rangement in which a stringv of tubing is arranged within the parts, leaving the sub in place.

drill pipe anddrilling fluid is circulated downwardly through the annulus between the drill pipe and the tubing, out through the bit, and up through the tubing. I The body of the bit and the sub together have connecting fluid passages as hereinafter described communicating with ihe annulus between the drill pipe and the tubing and extending downwardly and outwardly through the bottom of the bit, and have other fluid passages extending upwardly through the bit, and the sub, communicating with the inside of the tubing.

According to the invention the body of the bit is cylindrical, and with the sub, to which it is connected by threads, as described, forms a downward extension of the drill pipe which is characterized by its continuous, smooth, unbroken peripheral surface.

An important feature of the invention is that the body of the bit, which is cylindrical, as'stated, forms a'shroud extending downwardly around thecu'tters and substantially enclosing them, leaving only the lower portions of the cutters exposed,

The body of the bit,which necessarily is characterized by its ruggedness and its resistance to wear and deformation, advantageously may be formed initially as three separate lsegments, each of forged steel which are thereafter welded together. The sub maybe formed, by machining, from a length of steel shafting. I

An advantageous feature of the invention is that the bit is separable from the sub whereby it may be conveniently removed, and taken to the shop, for repair or replacement of The invention will be readily understood by referring to the following description and the accompanying drawing, in

which: 7

FIG. 1 is a longitudinal view, partly in quarter section and partly broken away,showing a well drilling bit and a special sub thereforeembodying the invention operatively connected to a string of drill pipe, shown fragmentarily, having tubing arranged therein concentrically thereof;

FIGS. 2 to 5 are transverse views showing the tops and bot- 1 toms of the sub, and of the bit, respectively; and

F I68. 6 and 7 show the tubular spear hereinafter described in its detached position.

Referring to the drawing, the numeral 1 designates 3 generally a well drilling bit embodying the invention, as hereinafter described, and the numeral 2 indicates generally a special sub, as hereinafter described, which forms an adapter wherebythe bit 1 is connected tothe lower end of a string of drill pipe, shown fragmentarily in FIG. 1 and indicated generally by the'numeral 3.

The bit'l and the 'sub 2 therefore are intended for use in an arrangement in which a string of tubing, shown fragmentarily in FIG. 1 and indicated. generally by the numeral 4, is arranged concentrically within thedrill pipe 3 and drilling fluid is circulated downwardly through the annulus between the drill pipe 3 and the tubing 4, out through the bit 1, and up through the tubing 4.

The body of the bit 1, designated generally by the numeral The bit 1 has a plurality of three circumferentially spaced,

' cone shaped cutters 6 rotatably mounted on the lower end of the body5 thereof, in conventional manner.

The body 5 of the bit 1, which is cylindrical, as stated, forms a shroud extending downwardly around the cutters 6 and sub stantially enclosing'them, leaving only the lower'portions of the cutters 6 exposed.

In the arrangement above described the cuttings from the well bore are positively prevented from passing upwardly around thebit 1 and are directed upwardly through the center thereof, through the tubing 4.

The body 5 of the bit 1, which necessarily is characterized by its ruggedness and its resistance to wear and deformation, advantageously may be formed initially as three separate l20- segments, each of forged steel, which are therein welded together.

The sub 2 may be formed, by machining from a length of steel shafting.

The bit 1 is separable from the sub 2 whereby it may be conveniently removed, and taken to the shop, for repair or replacement of parts, leaving the sub 2 in place. It is not necessary to dismantle the sub 2, or to handle it at all, inorder to repair the bit 1.

The body 5 of the bit 1 and the sub 2 together have connecting fluid passages as hereinafter described communicating with the annulus between the drill pipe 3 and the tubing 4 and extending downwardly and outwardly through the bottom of the bit 1, and have other fluid passages extending upwardly through the bit 1, and the sub 2, and communicating with the inside of the tubing 4.

The body 5 of the bit 1 has a central longitudinal bore 7 beginning at its lower end, and has an upstanding, externally threaded stem 8, of relatively smaller diameter, whereby it is connected to the sub 2. The stem 8, which is tubular, and immediately surrounds the bore 7, in fluid communication therewith, is of progressively reduced diameter in the direction of its upper end. The bit 1 has an upwardly facing shoulder 9 which surrounds the stem 8 at its base.

The lower-end portion of the sub 2, which is solid, has a central longitudinal bore 10 extending through it. The bore 10 is of progressively reduced diameter in an upward direction,

and is internally threaded, for a portion of its length beginning immediately surrounding the central bore 10 and in fluid communication therewith. The upper'end of the nipple 12 is received in the lower end of the tubing 4, in frictional engagement therewith.

The sub 2 has a plurality of circumferentially spaced fluid passages 13 extending longitudinally through the solid lowerend portion thereof, surrounding the central bore 10, and

. communicating at their upper ends with the annular space in the hollow upper-end portion of the sub 2, surrounding the nipple 12.

The sub 2 has a comparatively deep, downwardly facing annular groove 14 in the extreme lower end thereof. The groove 14 is in fluid communication with the longitudinally extending fluid passages 13, and forms a fluid course for use as hereinafter described.

The inner and outer peripheral walls of the groove 14 are formed by a pair of integral rings l5, 16, which are comparatively narrow relative to their height and are beveled on the outside "along their lower edges, for use as herein after described.

The upwardly facing shoulder 9 on the body 5 of the bit 1 forms a bottom closure for the downwardly facing annular groove 14 of the sub 2,-and has a pair of correspondingly beveled, upwardly facing grooves l7, 18 therein in which the lower ends of the rings 15, 16 forming the inner and outer peripheral walls of the first mentioned groove 14 are seated.

The grooves l7, l8 fonn a fluid tight seal with the rings l5, l6, and prevent the rings 15, 16 from spreading, due to fluid pressure.

The body 5 of the bit 1 has a plurality of three circumferentially spaced fluid passages 19 extending longitudinally thereof, beginning at its lower end, surrounding the central bore 7. The longitudinally extending fluid passages 19, which are arranged between the adjacent cutters 6 of each pair, each communicate at its upper end with a pair of upwardly diverging fluid passages 20, of relatively smaller diameter, as hereinafter described.

The three pairs of upwardly diverging fluid passages 20 terminate in circumferentially spaced openings in the upwardly facing shoulder 9 on the body 5 of the bit 1, between the lastmentioned grooves 17, 18, and are positioned opposite circumferentially spaced openings in the downwardly facing annular groove 14 of the sub 2 corresponding to the fluid passages 13 thereof, in fluid communication therewith.

The invention may be modified in various ways without departing from the spirit and scope thereof.

lclaim:

1. In combination with a string of drill pipe having a string of tubing arranged concentrically thereof, the combination of a well drilling bit and a sub therefore forming an adapter whereby the bit is connected to the lower end of the drill pipe, the bit having a unitary cylindrical body, formed in its entirety of forged steel, having a maximum diameter corresponding to the diameter of the sub, and having a plurality of three circumferentially spaced, cone shaped cutters rotatably mounted on its lower end, the body of the bit forming a shroud extending downwardly around the cutters and substantially enclosing them, the body of the bit having a central longitudinal bore beginning at its lower end, and having an upstanding, externally threaded stern immediately surrounding the central bore, and in fluid communication therewith, whereby it is connected to the sub, and the body having an upwardly facing external shoulder immediately surrounding the stem at its base, the sub having a solid lower-end portion, and having a hollow upper-end portion formed by an internally threaded peripheral wall whereby it is connected to the drill pipe, the sub having a central longitudinal bore extending through the solid lower-end portion thereof, said last mentioned bore being internally threaded beginning at its lower end whereby it is connected to the stem of the bit, and a short, tapered nipple being connected by threads to the solid lower-end portion of the sub, immediately surrounding the bore thereof and in fluid communication therewith, and extending upwardly therefrom for frictional engagement with the lower end of the tubing, the body of the bit and the sub having an annular fluid course in the meeting faces thereof formed by the upwardly facing shoulder of the bit and the corresponding, opposing surface on the lower end of the sub, immediately surrounding the central longitudinal bores thereof, and the sub having a plurality of circumferentially spaced fluid passages extending longitudinally through the solid lower-end portion thereof, communicating at their upper ends with the annulus between the upstanding nipple and said internally threaded peripheral wall, and communicating at their lower ends with said fluid course, and the body of the bit having a plurality of circumferentially spaced fluid passages communicating at their upper ends with a said fluid course and terminating at their lower ends between the cutters of the adjacent pairs. 1

2. The structure of claim 1, said fluid course being formed in part by a downwardly facing annular groove in the lower end of the sub, in opposing relation to the upwardly facing shoulder on the body of the bit, the inner and outer peripheral walls of said groove being formed by a pair of integral concentric rings, comparatively narrow relative to their height, the lower edges of which are beveled on the outside, and said upwardly facing shoulder having a pair of correspondingly beveled grooyestherein for seating engagement by said rin s, forming a fluid tight seal and positively preventing lateral isplacement of said rings.

3. The structure of claim 2, said circumferentially spaced fluid passages in the body of the bit consisting of a plurality of three fluid passages extending longitudinally of the body, beginning at its lower end, terminating a at their lower ends between the cutters of the adjacent pairs and each communicating at its upper end with a pair of upwardly diverging fluid passages, of relatively smaller diameter, which terminate in circumferentially spaced openings in said upwardly facing shoulder.

4. In combination with a string of drill pipe having a string of tubing arranged concentrically thereof forming a central flow passage and an annular flow passage, a cylindrical sub having a first bore extending longitudinally therethrough; means for securing the upper end of the sub to the drill pipe; a solid end portion on the lower end of the sub closing the lower end of the said first bore; said solid end portion having a bore extending longitudinally therethrough; a hollow stem having one end secured to the solid end portion of the sub and the other end adapted to be telescopically secured to the lower end of the tubing string such that the bore through the solid end portion of the sub, the hollow portion of the stem, and the central flow passage through the tubing are in fluid communication; passages through the solid end portion of the sub circumferentially spaced around the bore which extends therethrough, said passages being in fluid communication with the annular flow passage between the drill pipe and the tubing; an annular groove formed in the lower surface of the solid end portion of the sub, said annular groove being in fluid communication with said passages through the solid end portion of the sub; a drill bit; a cylindrical body on said bit; said body having a bore extending longitudinally therethrough; cutting means adjacent the lower end of the body of the bit; means to detachably secure the upper end of the body of the bit to the lower end of the sub such that the bore through the bit is in fluid communication with the bore through the solid end por- 

